Change /dev/zero in MINIX to produce 'a'

Question

For a project I have to change the zero-driver to produce an infinite amount of 'a' instead of the usual zero. So I modified /usr/src/drivers/memory/memory.c

This was the original:

/* Initialize /dev/zero. Simply write zeros into the buffer. */
for (i=0; i<ZERO_BUF_SIZE; i++) {
    dev_zero[i] = '\0'; //This is line 247
}

This is my modification:

/* Initialize /dev/zero. Simply write zeros into the buffer. */
for (i=0; i<ZERO_BUF_SIZE; i++) {
    dev_zero[i] = 'a'; //This is line 247
}

So I save and close and recompile memory.c but no changes when I say cat /dev/zero. I even tried deleting /dev/zero and using mknod /dev/zero c 1 5 to create a new one. But still no changes. I also tried rebooting.

Am I changing the incorrect file or am I not compiling the right files?

score 0 · Answer 1 · answered Aug 24 '15 at 16:25

0

Assuming you are editing the kernel source code, you probably need to reboot to see your changes take effect.

answered Aug 24 '15 at 16:25

hymie

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As I stated in the question, I tried rebooting. No change is observed. – Armand Maree Aug 24 '15 at 16:35

score 0 · Accepted Answer · answered Aug 24 '15 at 17:23

Okay I found that doing the following solves the problem:

cd /usr/src/drivers/memory/
make
cd ..
make clean
make build
make install
cd ..
make world
make install
cd kernel
make clean
make
shutdown

So basically recompiling a few directories and then restarting the OS.

Change /dev/zero in MINIX to produce 'a'

2 Answers2